The present invention relates to a method and apparatus for releaseably attaching a hub filler to a take-up reel to prevent deformation of an attached tape.
Single reel tape cartridges are used to transport and store tape for reelto-reel tape drives. A single reel tape cartridge is inserted into a tape drive and a mechanism is used to load the end of the tape into a take-up reel from the tape cartridge. Once the end of the tape is loaded into the take-up reel, the tape drive operates as a reel-to-reel tape drive. A motor is coupled to the take-up reel to rotate the take-up reel about the take-up reel axis and another motor is coupled to the single reel tape cartridge to rotate the reel of the tape cartridge about its axis.
The tape drive loading mechanism attaches to a tape leader pin, located at the end of the tape contained in the single reel tape cartridge. The hub filler uses a slot in the hub filler for receiving the tape leader pin. The hub filler is coupled to a guide arm that drives the hub filler between the single reel tape cartridge and the take-up reel. An example of a mechanism for driving the hub filler between the tape cartridge and the take-up reel is disclosed in U.S. Pat. No. 6,034,839.
FIG. 1 is a view of the tape drive loading mechanism disclosed in U.S. Pat. No. 6,034,839. The hub filler 300 enters into the cartridge 210 and attaches to the end of the tape. The hub filler 300 then moves along a guide rail 247, driven by the guide arm 250. Typically, the hub filler 300 attaches to the end of a tape in the tape cartridge 210 and the guide arm 250 moves the hub filler 300 along the guide rail 247, trailing the tape across the read/write head 222 and into the take-up reel 242. The hub filler 300 enters the take-up reel 242 through a channel 244 and into the hub 245 of the take-up reel 242.
FIG. 2 is a top view of the tape drive, depicting the hub filler 300 in the take-up reel 242 with the tape 216 attached. The tape 216 passes across the read/write head 222 and the end of the tape 216 is secured to the take-up reel 242. The tape drive is then operated by rotation of the take-up reel 242 and the single reel of the cartridge 210 about their respective axes to move the tape 216 across the read/write head 222. Motors are used to rotate the take-up reel 242 and the single reel of the cartridge 210, controlling the speed of the tape 216 as it moves across the read/write head 222. The hub filler 300 pivots on an axle 252 that is coupled to the guide arm 250. This pivoting is necessary for the hub filler 300 to be guided on the guide rail 247 into the take-up reel 242. Once the hub filler 300 is in the take-up reel 242, with the tape 216 attached, the take-up reel 242 rotates to thereby unload the tape from the cartridge 210. The hub filler 300 rotates with the take-up reel 242 on the axle 252. The loading mechanism attempts to align the axle 252 axis and the takeup reel 242 axis perfectly.
FIG. 3 is a top perspective view of the hub filler 300 partially ejected from take-up reel 242. It is shown that tape 600 is wrapped around the take-up reel 242 with a partially ejected hub filler 300. The partially ejected hub filler 300 prevents the tape 600 from wrapping on the circumference 602 of the take-up reel 242. As the tape 600 is progressively wrapped around the take-up reel 242 with the partially ejected hub filler 300, the partially ejected position of the hub filler 300 is maintained. This is due to both the pressure from the end of the tape 600 attached to the hub filler 300 and the force of the tape 600 on the hub filler 300 as it is wrapped around the take-up reel 242.
FIG. 4 is a cross-sectional view of the hub filler 300 partially ejected from the take-up reel 242. This figure also illustrates the misalignment of the axis 244 of the take-up reel 242 and the axle 246 of the hub filler 300.
There are some concerns regarding the conventional tape drive loading mechanism described above. After a hub filler has entered a take-up reel, the take-up reel is rotated by a motor to wrap tape around the take-up reel. However, there is a tendency for the hub filler to partially eject from the take-up reel during the initial rotation of the take-up reel. This ejection may be caused by the centrifugal force on the hub filler from the rotation of the take-up reel. The ejection may also be caused by other forces exerted on the hub filler, such as force from attached tape. After the initial wrapping of tape around the take-up reel, the position of the partially ejected hub filler in the take-up reel is relatively stable. This stability is a result of the force of the tape on the hub filler as the tape is wrapped around the take-up reel. This situation is the cause of several problems.
One problem is that the partially ejected hub filler disturbs the intended circumference portion of the take-up reel, around which the tape is intended to be wrapped. The hub filler is designed such that when the hub filler is properly positioned in the take-up reel, the circumference of the take-up reel is smooth all around. This smooth circumference preserves the integrity of tape that is wrapped around the take-up reel. A partially ejected hub filler disrupts this smooth circumference of the take-up reel and can damage tape wrapped around the take-up reel. This damage can be a bump or print formed on the tape from the portion of the hub filler that is protruding from the take-up reel. This bump or print is undesirable, as it will distort the quality of the data stored on the tape where the bump or print is formed. Also, the bump or print may deteriorate the mechanical strength of the tape and may eventually result in tape breakage.
Another concern related to a partially ejected hub filler from a take-up reel is the possibility that, as tape is progressively wrapped around the take-up reel, the pressure from tape on the hub filler will force the hub filler into the take-up reel. This is a problem because the hub filler is in a locked position after the initial wrapping of tape around the take-up reel. This forcing of the hub filler into the take-up reel puts mechanical stress on the tape near where the end of tape is attached to the hub filler. Accordingly, the tape may either be stretched or broken during this forced insertion of the hub filler into the take-up reel. As tape is progressively wrapped around a take-up reel, the pressure on the initially wrapped tape is also progressively increased. This pressure on the tape leads to stretching or breakage of the tape and distorts the stretched portion of the tape. There is also the possibility that the stretching of the tape will cause the tape to break or collapse. All of these types of damages to wrapped tape are undesirable and compromise the reliability of a tape drive.
Another concern relates to the alignment of a hub filler""s axle and a take-up reel axis. Misalignment can cause minor imbalances during rotation of the take-up reel; these minor imbalances can create small speed variations in the tape wind and unwind speeds. These variations in speed are difficult for the motors of the take-up reel and cartridge reel to compensate for. Hence, the variations in speed deter from the quality of the reading and writing of the tape at the read/write head. Additionally, misalignment of the hub filler axis and the take-up reel axis reduce the life of the bearings in the take-up reel. Worn bearings will produce vibrations and result in noise during recording and reading at the read/write head. A partially ejected hub filler from the take-up reel can cause such a misalignment and therefore result in a tape drive being unreliable.
There is a need for a tape drive loading mechanism that can releaseably attach a hub filler to a take-up reel. There is also a need to prevent the unintended ejection of the hub filler from the take-up reel to prevent damage to tape wrapped around the take-up reel. There is also a need for prevention of this unintended ejection causing damage to the tape drive.
These and other needs are met by embodiments of the present invention, which provide means for controllably and releaseably attaching a hub filler to a take-up reel during loading of tape from a tape cartridge to a take-up reel. In certain embodiments, an attachment mechanism is provided between the take-up reel and the hub filler. The hub filler can be controllably and releaseably attached to the take-up reel to prevent the ejection of the hub filler from the take-up reel during the period of operation when the tape is being initially wrapped around the circumference of the take-up reel. Specifically, the present invention may utilize magnetic force or mechanical force to attach the hub filler to the take-up reel.
One of the advantages of certain embodiments of the present invention is the substantial prevention of the partial ejection of the hub filler from the take-up reel during the initial wrapping of tape around the take-up reel. This prevents unnecessary damage to the tape and tape drive mechanism. Specifically, if a hub filler is correctly attached to the take-up reel, the circumference of the take-up reel will be smooth during the initial wrapping of tape. As the circumference of the take-up reel is smooth, it is unlikely that a bump or print will be formed on the tape, which would result from a hub filler partially ejected from a take-up reel. Additionally, the tape drive mechanism of the present invention mitigates the likelihood of the tape wrapped around a take-up reel breaking, stretching, or collapsing. This breaking, stretching, or collapsing is prevented because the hub filler of the present invention is not forced into the take-up reel of the present invention after the initial wrapping of the tape. The tape drive of the present invention also minimizes misalignment of the hub filler axle with the take-up reel axis, so as to prevent the mechanical wear resulting from continued operation of a misaligned hub filler.